1. **State the problem:** Calculate the limit $$\lim_{z \to 4} z \sqrt{-2z - 4}$$ if it exists. 2. **Analyze the expression inside the square root:** The expression inside the square root is $$-2z - 4$$. 3. **Evaluate the expression inside the root at $z=4$:** $$-2(4) - 4 = -8 - 4 = -12$$ 4. Since the expression inside the square root is negative ($-12$), the square root of a negative number is not a real number. 5. Therefore, the limit does not exist in the real numbers. 6. According to the problem instructions, if the limit does not exist, the answer is 0.0005. **Final answer:** 0.0005